下面五位同学在人际交往中遇到了一些问题，请从A-E中选择适合他们的一条建议。
( )1. I hate a classmate of mine because she always speaks ill of (说某人的坏话) me.
( )2. I argued with my friend Eve again because she never understands me.
( )3. I can't make friends with Jim because he is different from me. I can't stand that.
( )4. I have few friends because I won't know how to make friends. It seems that I have
no interest in anything except my books.
( )5. My friends all complain that I don't keep my promise (信守诺言). I'm very sad.
A. If you promise others, you must keep it. If you can't, don't make any promise.
B. Don't care too much about what others say about you. Just be yourself if you're right.
C. Try to show an interest in others. If you do so, you will find it's easier to make friends.
D. Try to understand others first. Then you can be understood well.
E. It's not necessary to be the same. Respect (尊重) others. Don't hope that all friends are
the same as you.
2O3．某物质中只含有一种元素，该物质是[ ]